Sorry for such a delayed response - but yes, I also thought I would have bought from the apple store on my phone. If that makes it in any way recoverable, the apple account used I think should have been registered to this same email I'm now using on this forum?

It may have been from many years ago, I have files on this laptop pro version that date back to 2015-2016, if that might be early enough for it to be that? I did also try password reset with all of my email accounts, but didn't receive a reset email to any of them. checked junk etc. too incase it was something like that.